But it's Ortiz's torrid start that's helped carry Boston's offense. He hit .405 in April with six homers and 20 RBIs, posting a .543 average in Fenway Park (19 for 35).

"David's the star of star's right now," Boston manager Bobby Valentine said. "He's hitting to all fields. It's hard to get a strike by him. The swing is probably as good as it can get."

It was Boston's seventh win in eight games, coming off a 6-1 road trip.

Former Red Sox outfielder Josh Reddick hit a three-run homer for offensively challenged Oakland, which dropped its third straight. The A's entered the day having scored the majors' second fewest runs (67) behind only Pittsburgh's 46.

When the Red Sox left town after their initial homestand of the season, they were on a five-game losing streak and had just blown a 9-0 lead in a loss to the rival Yankees.

Boy, how things changed.

Boston charged through Minnesota and Chicago, only losing the finale of a four-game series against the White Sox and returned to Fenway looking like a team that was expected to be strong in the AL East.

On Monday, they knocked around A's starter Tommy Milone (3-2) for eight runs -- seven earned -- in 4 2/3 innings en route to an 11-1 lead after five innings.

Milone had retired 22 of the 26 lefties he faced until Ortiz homered leading off the second, the first of two he gave up to the big slugger.

"Both fastballs," he said. "They were supposed to be a little more in than they were. But, you know, caught too much of the plate and obviously a good hitter like that is going to hit those pitches."

After the big lead, the Red Sox almost reverted to that ugly loss against the Yankees before Vicente Padilla escaped a bases-loaded jam by striking out Daric Barton in the seventh. Reddick bounced into an inning-ending double play with the bases-loaded in the eighth.

Buchholz (3-1) gave up six runs on seven hits, walking five and striking out five in 6 2/3 innings.

Oakland cut it to 11-6 in the seventh, with Coco Crisp getting a two-run single before Reddick hit his homer.

Milone, who had a pair of eight-inning scoreless outings in his first four starts, had given up only six total runs in his previous starts.

Trailing 1-0, the Red Sox scored four in the second. Ortiz, in his 15th season, led off with a homer into the A's bullpen, Byrd and Aviles had RBI singles, with Aviles later scoring on second baseman Jemile Week's throwing error.

McDonald homered off a light-tower in left-center to make it 6-1 in the third.

The Red Sox then chased Milone during a five-run fifth. Ortiz homered into the Red Sox bullpen to make it 7-1, a drive that right fielder Reddick made a leaping attempt on, and had the ball tip off his glove before he fell into the pen. A member of the Red Sox picked up his hat and handed it to him before he hopped back onto the field.

"That's actually the first time I've had a chance to rob one," he said. "I've done it 1,000 times in batting practice and never had it in a game."

Byrd had an RBI double against reliever Jordan Norberto and Aviles hit his three-run homer into the Green Monster seats to make it 11-1.

The A's had taken a 1-0 lead in the second when Kurt Suzuki scored from third as the Red Sox caught Barton in a rundown.

Game notes
It was Ortiz's 38th career multihomer game, 36th with Boston. He's one behind Ted Williams for most in club history. ... Red Sox 3B Kevin Youkilis was a late scratch with tightness in his lower back. He also missed Sunday's loss in Chicago with the same injury. ... Reddick, traded from the Red Sox in an offseason deal that brought OF Ryan Sweeney and injured closed Andrew Bailey, played his first game against his former team. "I hope I can go out and have a few good games and show my former team what they're missing," he said before the game. ... Buchholz has now allowed at least five runs in each of his five starts.